need an optical switch to run some LED's

im building a boat. we are filling the interior with cool white LED scripts, going down the stairs, under cabinets leading to the bathroom, closets, everywhere. one of the things i would like to do is hook up each zone to an optical motion sensor switch. similar to security lights you would put in your back yard, it sees motion, it turns on and stays on for a configurable amount of time, most likely 5 minutes.

here's the rubs. one, it needs to be 12 volt. two, ive found them where they are the size of a wall plate, but i need them smaller, im thinking i drill a 1/2 hole in something and insert the sensor.

i found these, which seem to be what i want
http://www.bannerengineering.com/en-...7/SB12-Series/

but i don't know enough about electronics to read the specs very well. it looks like these plug into some kind of relay (which i know how to do) and it switches the relay on and off. but if thats the case, where does the timer come in? it looks like the timing is done in the relay unit and if i put this to a simple relay all it will do is switch the lights on when it senses motion and switch it off when it doesn't

i need some help with this guys.

thanks